The present invention generally relates to packaging for sterile tissue specimens for use in tissue transplant and more specifically to packages for allograft implant tissue forms in specifically designed sterile packages or containers which prevent lipid collection around the implant form.
Allograft tissue forms are useful in orthopaedic and neurosurgery. In practice, processed human tissue is delivered to the hospital and eventually to the surgeon in a form useful for surgical implantation in a sterile package. Unfortunately, while large amounts of time have been spent on development and processing of the tissue implant form, little consideration has been spent on the package design and the specific problems involved with packaging bone implant forms constructed of demineralized, partially demineralized or mineralized bone. Packaging that is currently used for bone implant forms is cumbersome and it is often difficult to easily remove the implant form from such packaging while wearing gloves during a surgical procedure. Furthermore a need has developed for a simple, inexpensive packaging that may be used to safely retain implant allograft forms in a sterile condition away from the lipid pooling while allowing storage of same and maintaining sterility up until the actual time of implantation during surgery.
There are presently available a number of kinds of packaging for sterile specimens. One form of commonly used packaging is to provide the allograft tissue in a freeze-dried state in a glass bottle with a stopper or other waterproof container. This type of packaging provides the advantage of stabilizing the tissue for storage in a warehouse or hospital supply room at normal room-temperature conditions. Freeze-dried packaging works effectively for relatively small sizes of allograft tissues such as demineralized bone powders, chips, and small machined shapes such as pins, screws and spinal spacers.
Another form of packaging which has been used for holding products such as a pre-sterilized medical devices and allograft implant forms are sealed blister containers. Such containers generally comprise a relatively rigid blister tray with a peripheral flange and a foil composite material or paper backing sheet positioned over the open tray in overlapping engagement with the peripheral flange forming a cover. The cover is manually peeled-away from the flange to which it is sealed to allow access to the medical device or implant tissue form contained therein. Other examples of packaging for medical devices or implant forms which have been utilized or are known in the art are shown in the following patents.
U.S. Pat. No. 6,012,580 is directed toward a clamshell type package with two halves pivoted together at a hinge constructed of a transparent plastic constituted to serve as a universal package for implant materials.
U.S. Pat. No. 5,720,391 shows a blister package and insert holder for a heart valve prosthesis. The package is constructed with an outer tray which receives an inner tray. An inner tray lid seals the inner tray and is provided with a pull tab on its exterior surface so that the same can be pulled away from the lip of the inner tray for access to the sterile heart valve prosthesis. The outer tray is provided with a tray lid which is sealed to the lip of an outer flange of the outer tray.
U.S. Pat. No. 5,690,226 shows a sealed air tight molded blister package of PETG having a hollow interior with the opening surrounded by an outwardly extending flange. A multi-layer peelable cover is sealed to the flange surrounding the opening. The cover and the flange are deformed towards the bottom of the container from the plane of the opening sealed by the peelable cover.
U.S. Pat. No. 5,615,770 discloses a sterilizable medical implant package insert placed within a standard sterile implant package holding an implant and allowing for the automatic presentation of the implant from the insert when the sterile package top is opened.
U.S. Pat. No. 5,257,692 is directed toward a three envelope package for preserving tissue specimens or other sterile objects. The sterile tissue sample is sealed within an innermost envelope which is sterile inside and outside. The innermost envelope is sealed within the sterile interior of an intermediate envelope which is both sterile inside and outside. This intermediate envelope is made of foil or another substance impermeable to a storage medium such as liquid nitrogen and is sealed within the sterile interior of an outermost envelope made of foil or another substance impermeable to a storage medium. The outermost envelope provides complete impermeability to liquid nitrogen, eliminating the possibility of nitrogen seepage through the peel-baked seal of the intermediate envelope.
U.S. Pat. No. 5,176,258 shows a package with a peripheral flange around a blister defining an open cavity for receiving a product and a compressible insert for securing the product against movement in the package cavity. At least one projection on the insert extends laterally from the cavity over the peripheral flange and a lid covering the cavity is continuously sealed to the peripheral flange and the projection along a single seal.
U.S. Pat. No. 4,750,619 is directed toward a package for a sterile prosthetic implant element comprising an outer receptacle and an inner receptacle which fits into the cavity of the outer receptacle. Both of the receptacles are provided with outwardly extending flanges surrounding the outer periphery of the cavity of each receptacle and receive a lid which is secured thereto. A tray received within the inner receptacle has hinged leaves so that upon placement of the tray within the receptacle and folding the hinged leaves, the prosthetic implant element is confined within a defined envelope to protect the same against damage.
U.S. Pat. No. 4,697,703 discloses a double sterile package for medical items such as a hip joint prosthesis with an outer open container enclosing an inner package containing the medical item. The inner package has a first insert contained in the open top container, a lid and a second insert carried by the lid. The outer container is sealed with a cover which engages an outer peripheral flange formed around the open top of the outer container.
None of the above noted packages are conducive to implants formed of bone and other tissue. Animal bone tissue forms, after processing, include lipids sometimes called structural fats. Lipids are a group of fatty substances that include fatty oils, waxes, sterols such as cholesterol, triglycerides (the principal forms of fat in body fat) and esters of fatty acids containing groups such as phosphoric acid (phospholipids) and carbohydrates (glycolipids). Over time, the fatty oils contained in the processed bone material are drawn out of the bone and are absorbed by the permeable cover and begin to dissolve the adhesive bond between the cover and the container. This activity causes the cover to separate from the container receptacle destroying the sterility of the package and leaving pools or rivets of a dark oily material which is unsightly and causes the surgeon to discard or send back the tissue form. This lipid migration is a serious problem for manufacturers of forms of allograft bone, and presents problems for the hospital and surgeon user. Accordingly, a double sterile package container assembly has been developed to handle bone implant forms of allograft tissue which resolves these problems.
The present invention is directed toward an allograft tissue package constructed to hold allograft bone tissue implant forms in a sterile inner package allowing drainage of the lipids contained in the implant without destroying the seal and sterility of the package. The package for storing sterile allograft tissue implant forms is constructed with an outer container defining an open faced cavity and a flange extending outward from said cavity with a stepped recess formed in said flange surrounding the cavity. An inner container which is adapted to be seated in the cavity of the outer container defines an open faced cavity and a flange extending outward from said cavity, the inner container flange being of a dimension to fit into the stepped recess of the outer container. An insert member sized to fit into said inner container cavity defines a shaped depression thereinto hold a tissue implant form within a designated space defined by the shaped depression.
The inner container is covered by a permeable cover sealed to the flange of the inner container allowing the tissue form to be treated and the outer container is covered by an impermeable cover sealed to the flange of the outer container covering the outer container cavity.
It is an object of the invention to provide a packaging system which holds specially constructed tissue forms in a double sterile condition which allows a user to peel away a cover to reach the inner tissue container and then peel away a cover to provide access to the tissue form.
It is yet another object to provide a sterile package for implant forms up to the point where the implant is presented to the surgeon for implant.
It is another object of the invention to provide a medical package in which an implant tissue form can be maintained in a double sterile condition.
It is still another object of the invention to provide a package for storing sterile tissue implant forms for later use in an implant situation.
It is yet another object of the invention to provide a package for storing tissue implant forms whereby the tissue implants forms can be removed from the package in a sterile condition.
It is still another object of the invention to provide a sterile tissue package which allows treatment of the tissue form while it is contained in a sterile package.
It is yet another object of the invention to provide a sterile tissue package which can be stored for treatment in a position that saves package space within the treatment apparatus.
In the accompanying drawings, there is shown illustrative embodiments of the invention from which these and other objectives, novel features and advantages will be readily apparent.